Graduate Engineer, Signal Processing

Job description

The world still has coverage blind spots. You could help eliminate them at Skylo.   Skylo has pioneered a standards-based approach to satellite connectivity. We connect smartphones and IoT devices directly to satellites. No special hardware, no entirely new networks. Just billions of existing devices, suddenly reachable anywhere on Earth. We're not building toward this future. We're already in it.   Our direct-to-device service is live on millions of activated devices across five continents, covering more than 72 million square kilometers, in partnership with leading satellite operators, mobile network operators, Tier-1 chipset makers, and OEMs worldwide. And we're just getting started.   At the heart of it all is Skylo's commercial NTN vRAN: a 3GPP standards-based, cloud-native platform that seamlessly bridges terrestrial and satellite networks. It's the infrastructure that makes true anywhere, anytime connectivity possible.   When you join Skylo, you'll work at the intersection of three markets reshaping how the world stays connected: mass-market consumer devices, automotive, and industrial IoT. Enabling people outdoors and critical workflows in the world's most remote places.   This is a rare chance to work on technology that matters, at a company that's already proving it works This role is based in Espoo, Finland, one of Skylo's core engineering hubs and fastest-growing sites. You'll work onsite three days a week as part of a team that's scaling quickly. HOW YOU WILL IMPACT SKYLO Skylo is looking for a graduate engineer to join our Protocol Stack team, working on 5G New Radio Non-Terrestrial Network (NR-NTN) Layer 1 and Layer 2 protocol implementations. You'll learn to design, implement, and validate PHY, MAC, FAPI, and scheduler software running on Skylo's NTN vRAN platform — with mentorship from senior engineers and close collaboration with our RF, systems, and integration teams. This is a hands-on role on real production software. You will not be writing throwaway code: what you build ships to a live satellite network.   WHAT YOU'LL DO - L1 Algorithm & Doppler Compensation: Design and implement 5G NR Layer 1 DSP algorithms for dynamic Doppler tracking, CFO pre-compensation, and ICI mitigation in high-velocity satellite environments. - Write and maintain C++ code within our 5G NR-NTN L1/L2 protocol stack — MAC, and DL/UL schedulers — starting with well-scoped modules and growing into larger components - Learn and implement NTN-specific L1 adaptations: extended HARQ round-trip timers, timing advance pre-compensation, NTN-aware link adaptation, and satellite Doppler pre-compensation - Contribute to MAC scheduler work for NTN: HARQ retransmission management, coverage enhancement (CE) mode scheduling, and constellation-aware resource allocation - Build test cases, simulation harnesses, and automation to validate L1/L2 behaviour against 3GPP specifications - Support lab and field validation of L1/L2 protocol behaviour across LEO/GEO NTN environments alongside RF and baseband engineers - Debug and root-cause issues in Linux environments using GDB, Valgrind, perf, and Wireshark — building the debugging instincts that define strong protocol engineers - Work with systems engineers to translate 3GPP Rel-17/18 NR-NTN specifications into software requirements - Participate in code reviews, architecture discussions, and technical documentation - Use AI coding assistants (Claude, Cursor, Codex) across the development lifecycle — from spec interpretation to test automation to code review — and help shape how the team works with them   SOUND LIKE YOU? WHAT YOU BRING Essential - Strong programming ability in C++ — you've written non-trivial C++ (university projects, internships, open source, or personal work) and understand memory management, pointers/references, and the standard library. This is our top priority. - Bachelor's, Master's, or PhD in Electrical Engineering, Wireless Communications, Telecommunications, Computer Science, or a closely related field - Working knowledge of digital communications and signal processing fundamentals: modulation, channel coding, OFDM, link budgets - Familiarity with 5G NR or LTE concepts from coursework, projects, or research — frame/slot structure, HARQ, scheduling - Comfortable working in Linux and with version control (Git) - Curiosity and persistence when debugging: you enjoy chasing a problem until you understand the root cause - Clear communication and a genuine appetite to learn from experienced engineers   Nice to Have - Internship, thesis, or research experience in wireless protocol development, baseband, or SDR (srsRAN, OpenAirInterface, GNU Radio) - Exposure to 5G NR PHY details: numerologies, PDSCH/PUSCH processing, beamforming, link adaptation - Exposure to 5G NR MAC: scheduling procedures, HARQ management, BSR/SR/PHR handling, random access - Awareness of FAPI (nFAPI or SCF FAPI) and split L1/L2 ar